Automobile air bag restraint systems commonly use pyrotechnic gas generants such as alkali metal azides to rapidly generate the relatively large amount of gas required almost instantaneously to inflate the air bag. The alkali metal azide generant is caused to ignite and burn, at temperatures of 2000.degree. F. and higher, to provide a high velocity gas stream. The combustion of the generant results in the formation of a relatively large amount of particles, some of which is hazardous and hence needs to be filtered from the gas stream before its entry into the air bag. Presently used filtering media involve the use of metal fibers and ceramics which can withstand the high temperature environment. Also, the very high temperature and caustic environment resulting from the use of alkali metal azide generants limits the effectiveness of common gasket materials and hence the effectiveness of the filter system.